Electrooptical transmission



Sept; 20, 1932. H. E. was

ELECTHOOPTICAL' TRANSMISSION Original Filed Sept. 10. 1927 2 Sheets-Sheet l Arm/m5) Sept. 20, 1932. H. E. IVES ELECTROOPTICAL-TRANSMISSION Original Filed Sept. 10. 192'T 2 Sheets-Sheet 2 i 1? N TED ICST ATE S;rATE r, ,orrlcn.

nn tnnmr or momrcmrn, new nsEY, ASSIGNOR To BELL 'rnnnrnonn m oj nnrromns, mcoaromlrnn, OE-NEW xonx,1w;Y.,-A coarona'rron on NEW YORK nnncrnoorrrcn. TRANSMISSION I gfi neaao filed September 1o, 1927, Ser1a1 no; cram. nenewea A r as, mo.

. This invention relates to electro-opti'cal to correct for thedflferent relative sensitivi "transmission and more particularly to the ties of thedifierent color sensit ve cells more electrical productionof images of moving obred than green, and. m r green han 1 .jects .or pictures intheir natural colors. sensitive cells may be used. Also, difierent In atelex 'isionsystem such as that disclosed degrees of amplificationma be used for the in the copending application of Frank Gray, d1 erent primary O e three cells 1' Serial -No. 227,649, filed Oct. 21, :1927, the groups thereof are sodisPosed around the 0 ,object whose image 1s to be produced elecect to be scanned as t'o aiford suhstantiall tricall y is illuminated point by point by an thesame pomt of-vlew of the ob ect for'a 0 intense beam of light passing through apercells of a set or grO P- S QQI lQQ tures in a rotating disc. Reflected light from gljea-tly devlated from, the transmitted-image the object falls upon alight sensitive cell and W111 h wc l r-frmge 1 is translated into electric current varyingin I} ne f rm of he nvention, at the re- ,amplitudein accordance with the varying-rey g 19 5. e ets of mtermeshed- 15 .fiecting ower of'the object from point to grld-hke l1 1g 9h gQ lamps 0 -255 point. guccessivescannings take place with c py n ll umma e heyv wmg field, a in the period of the persistence f yision; s g slmllarly Over o eud which isabout g of a second. jThe resultant .Q field- T 1 1 1 the fi m current. has frequency components lying lamps are preferably so" arranged thatjuxta- .4 Within a range from 0 to 30,000 or 40,000 posed strips of red,- green, and blue 1llum1- "m f; cyo1espr seoond of" which components it is nation are generated. Each .Of the lamps essential to transmit a major portion 'say arranged to produce strips of light of a from 101:0115 cycles and u th range .re--g1Ven color is ene gl e by a correspondmg ".quire'd being dependent upon the degree of -C .9l.' g msc nmgatthe trans- -z5 resolution to be obtained inithe' produced im-L g t Th 2 fi61 Il f y 75 age and the-size of the object. 7 lamps preferably eqntamflhree'dnierent The methods of scanning or analysis, and gases, POS S1bly 1n. con unct1onw th colored synthesis, as 'deyeloped and describ'ed in the g in the tube sectlons, s0 chqsen that the above mentioned application are limite'dfto grid arrangement 'presentsjuxtapo'sed "tube "monochrome television. Inaccordance with .S s of mp 80 thepresentinventi n means are tied for emlt r d, g e a d b ue ight, espect e ydeireloping theiip inciples of a ochrome vSm ll m nt l a as f c n o these i system intoath'ree-colorarrange nt forthe tubes are successively electrical y .e erg d electrical "production of picturesi{ .m the nat 1n v ylpg amounts y sm Wlth Q ural colors of the object-whose image is trans, spondlng elem ntal areas of the ob ect 85 i d 7 whoseimage is produced;- In an embodiment of the inventionchosen I another form, atthe receiving station, Y Y forillustration and described'in detailhereinhree-iglow. discha g mnps,- .01 for ch I after, three light-sensitive cells, each" 'selecp i a y' 816,50 a g a t e light 40 .tiye'by yirtue ofits' natural'sensitivity'or by ,fror'n each is simultaneously directed onto the o f-Fcolor filters to certainportions the entire field of view and by. means of a of the spectrum such as those corresponding suitable scanning arran' mentonly "one ele- ',to the primary colors, are excited by light mental area of the he d corresponding to .fiectedfro'm. the object. .The selective light that of'the' 'object being vscanned. i s ex'p0se' 1 sensitive cells are connected toith-ree ampli to wiew at any; instant.'-- Inthisarran gement-Oa --fier andcontrol networks, one for eachpr i' each lamp has anilluniinated area.- equal to 7 mary color, and these n turn are connected the whole tiewing field illuminated to three transmission channels. A plurality ateach .instantby each Y of light sensitive cells sensitive to each of the 1 cordzihce with th nmary colorin ectensity of the illu'ini'miprimary; colors may be used if desired, and -;1ti.0n of .an elemental area of the object whose;-

image is being produced but only one elemental area-of each lamp is exposed to view at any instant; while in the previously described arrangement only one elemental area of the lamps is illuminated at any instant. The transmitting arrangement may be the same for both receiving arrangements.

A more detailed description of the invention follows and is illustrated in the accompanyiig drawings.

Fig. 1 is a schematic representation of a color television system showing the electrical and mechanical terminal elements selected for illustrating this invention.

Fig. 2 is a partial detailed rear view of the grid type multiple electrode glow discharge lamps showing the 'uxtaposed positioning of the tube sections the three sets of lamps, one for each primary color. I

Fig. 3 isa cross section of one of the tubes of they glow discharge lamps.

Fig. 4 is a schematic representation of a modified receiving arrangement employing a rotating scanning disc for distributing the the scanning disc, the ,apertured screen 30,

whose opening 31 is so dimensioned that the light coming through only one aperture in the disc 22 can at any instant pass, and a lens 32, to the object 10 whose image is transmitted. The scanning disc 22 is rotated at a substantially uniform speed by the driving motor element 11. As the scanning disc is rotated it causes a small beam of intense light, passing successively through each one of its apertures, to scan in a' series of parallel paths the object whose image is transmitted, and reflected light from each elemental area of the objects so illuminated is successively impressed upon a plurality of color selective light sensitive translating devices 40, 41, and

arrangement applicable to t shown in the copending application of Frank.

the primary li ht color values of the ele- .mental areas 0 the object, and each is connected with an individual electrical transmission channel. Further details of a. single channel scanning and light translating is system are Gray, Serial No. 227,649, filed Oct. 21, 1927, supra. A suitable synchronizing system is disclosed in the patent of H. M. Stoller and E. R. Morton, N 0. 1,763,309, issued June 17, 1930.

sensitive cell in the transmitting station to the receiving lamps in the receiving station. Aplurality of groups of color selective light sensitive cells may be used and a second group 44, and 46 with their respective filters 54, and 56 similar to the first group are shown. The light sensitive cells responsive to the same color or spectral band are connected to the same channel. As heretofore stated the light sensitive cells of any group responsive to all of the different primary colors are positioned close together so as to view the object through as small an an gle as practicable in order to prevent. the separate channels producing their part of the received picture as though the object were illuminated by differently located colored light sources which would cause the produced image to show color fringes.

"At the selective light sensit've cells the light energy. in accordance wit the reflective power and the primary color value of the elemental area of the object being scanned is translated into electric current.- The electric current from each difi erent color selective light sensitive cell is amplified and con-. trolled by suitable amplifiers 60, Gland 62 for each channel, respectively. These a1uplifiers are arranged so that the amount of amplification can be adjusted as desired for each channel and thus permit adjusting the output current from all channels to the proper strength irrespective of any difference in response due to the sensitivity of the different light sensitive cells used for the difi'erent primary colors or spectral bands. The several channels are connected through repeating coils 70, 71, and 72 with the transmission lines 80, 81, and 82, respectively. The several transmission lines are in turn connected with receiving apparatus through the repeating coils 90, 91 and 92, respectively.

The incoming picture current transmitted over the several channels is impressed upon separate receiving amplifier and control networks 110, 120, and 130, for each channel, respectively. The transmitted current in the arrangement shown is an alternating current of varying amplitude representative of light variatlons above and below the average tone value of the primary colors of the object being scanned. The advantages of employing current of this kind and further details of apparatus'for its production are disclosed. in a copending application of H. E. Ives and gggray, Serial No. 181,511, filed April 6,

85 The selective light sensitive cells 40, 41 The alternating signal current received Ill.

' from each transmission channel after being impressed'upon its respective amplifier and control'networks 110, 120, and 130 is caused to modulate a high frequency oscillating cur rent generated by the oscillator 100. The modulated high frequency current of each channel is next passed through commutator distributors 150, 160, and 170 for each of the respective channels -and from these distributors to multiple electrode glow discharge lamps 200. The receiving, amplifier and control networks 110, 120, and 130 and the several distributor commutators are each similar to those shown for a single'channel system in the patent of Frank Gray, 1,759,504, issued May 20, 1930. The viewing field at the receiving station is illuminated by a set of three large multiple electrode glow discharge lamps, one electrode-on each set being employed for each elemental area of the field and one lamp for each of the primary colors. The distributor commutators glow discharge lamps.

sections for each "primary;

. to the proper intensity.

contain one contact for. each element or individual electrode of the glow discharge.

lamps and connection is made between them by individual wires. Each distributor commutator at any instant connects with only one electrode on the glow discharge lampgand thereb limits the illumination to the elementa area defined by the connected electrode. In this system the several channels, one for each prima color, operate simultaneously and at eac instant one elemental area for each channel or color is illuminated Each distributor commutator has a rotating brush and the brushes of all distributors are mounted on a single shaft but insulated therefrom and are driven synchronously and in phase with the,

scanning apparatus-by means ofthe driving rnotor element 103. The electrical circuits for the icture producing current flowing through t elow discharge lamps: are from individual e ectrodes on the lamps each of which connects with an individual contact in the distributor commutators, to the-common electrodes of the lamps. The multiple electrode glow discharge receiving light source, as heretofore stated, is divided into three separate lamps corresponding to the channels. By grouping or arranging the sections of each element so that the sections of each lamp are juxtaposed andone section of each channel is positioned at every third position across the viewing field',.the field is uniformly covered by the difierent channels or diiferentcolor producing elements of the The electrodes of the difierent color are connected to the proper channel.

various sections according to turn connect with the receiving amplifier and control networks 110, 120,

quency current may three primary colorsor' clos 'ely in frontof the glow discharge lamps and 130, respectively, of the variouschannels. The arrangement of the connections between the distributor commutator and the sections of the glow discharge lamp and of the common electrode with each section of the glow discharge lamps so as to uniformly distribute" the sections associated witheach channelpreferably provides for connecting every third tube section, since three primary color channels are employed, to their respective channels. This arran ement of the connections is shown in both%*ig. 1 and Fig. 2. .The circuit for the modulated high frequency picture current maybe traced for one channel from the receiving circuit network 110, conductor-111, slip ring 1 53, brush arm 152, distributor-brush 151, one of the contacts in the commutator distributor 150, one of the individual lead wires from such contact to circuit network 110. A similar circuit may be traced in connection with each of the'other channels. As many individual wires connect between the distributor commutator contacts and the glow discharge lamps as there are individual electrodes on the lam s, though in the drawing this plurality of w res is shown by a few single lines for simplicity.

The response of the glow discharge; lamp is much more sensitive to starting and to small current variations if the lamp is already under excitation when the signal current is" impressed thereon, and this fact is taken advantage of by continuously exciting the lamp through a; special set of electrodes so arranged as to avoid interfering with the This second high fretions of the lamp."

be supplied from a high frequency oscillator 101. One terminal of this oscillatorconnects by means of the conductor 102 to the auxiliary electrodes 205 on each tube section-of the glow discharge lamps, while the other terminal of the oscillator connects through the receiving circuil network of the several channels withthe commonelectrodes of-the glow discharge lamps through the several lamp common return conductors 122 and 132. The panel 220 positioned has a large opening which exposes toview the front side of the glow discharge lamps 200 producing a picture. For close viewing this :opening may contain a panel of. ground glass. Three channels have preferably been shown and described as this number re resents. the primary colors.- The operation 0 eachchanl nel is thesame as any other 'channelwith the exception that each light sensitive cell at the transmitting station is activated by its own selective light color or spectral band and each receiving lamp at the receiving station generates a light corresponding to one of the primary colors, and each channel is, with the exception above noted, in most respects substantially the same as that disclosed in the I of the light then only one gas containing chamber is necessarywith a gas which emits light having a continuous visible spectrum. The gas containing chamber of each lamp is composed of a plurality of glass tubes pos tioned parallel to each other in a flat gridlike formation and connected in series with each other at their ends. This arrangement forms a continuous chamber in which the gas pressure is the same throughout and one which may cover a large area and at the same time stand atmospheric pressure without having the walls of the chamber unduly thick. The various tube sections are fastened bya lacing or other suitable means to the left and right separating members 210 and 211.. Each tube section 201 has an interior common electrode 202 which may be in the form. of an open spiral conductor extending throughout the length of a section, and a plurality of spaced individual electrodes 203 fixed along the exterior rear side of the tube sections. These exterior electrodes may be made of tinfoil or other suitable conducting material cemented to the tube sections. They extend circumferentially about 180 and longitudinally along the tube length a distance about equal to three times the diameter of the tube and thus have a front or projected rectangular area having a length about three ,times the width. Each electrode is separated to insulate it from the adjoining electrodes by small distances which may be a small fraction of its length. The adjoining. tube sections are positioned in such proximity to each other that the exterior individual electrodes appear uniformly spaced throughout the entire area covered by the tubes. Three adjoining exterior electrodes preferably have a front or projected area which is substantially squareand when such adjoin ng'electrodes are energized the illuminated area is substantially square. The interior common electrode of each tube section is brought out at one end through a seal and connected-to one of the common conductors 112, 122 or 132 in a manner to preferably group the various sections into channels as heretofore demvamr scribed. A special or auxiliary set of exterior electrodes 205, heretofore referred to, associate with all of the tube sections forms a common connection to all. This connection is used for continuously energizing each section of the lamps by passing a high fre quency oscillating current from it across the end of each section to the interior common electrodes 202 to maintain a condition of ex citation of the tubes which substantially eliminates lag in the response of the lamps when energized by side of the chamber. If a direct current having a Voltage of the order of 150 volts is ap plied across these terminals, a discharge takes place which causes purification of the gas in the lamps in a well known manner.

A cross section of one of the tubular sections of a lamp is shown in Fig. 3. The relative position of the common internal electrode 202, the walls of the tube sections 201,

and the individual external electrodes 203 are clearly shown in this drawing.

The apparatus and the operation of this multi-channel color system is similar in many respects to that of a single channel system. In the multi-channel system, however, obviously certain apparatus servesall channels. The position of the portion of the image transmitted by each channel, on the viewing screen is such that at each instant, the three areas illuminated in accordance with the three primary colors at each instant represents an elemental area corresponding to the elemental area of the object being scanned. The threeprimary colors simultaneously appearing at any instant on the viewing screen preferably cover a square area divided between each of the three primary colors, each color being positioned in a strip about onethird the width of the illuminated area representing an element of the produced picture at any instant.

The system of Fig. 1 is a multi-channel system from the point of analysis of the light effects of the object into the three primary colors at the transmitting station to the point of reproducing the light effects in the three primary colors on the viewing screen at the receiving station where the eye directly views and optically combinesthe three primary colors on adjacent elemental areas of the viewing screen. A modification of the'receiving apparatus is shown in Fig. 4 in which the three primary colors are generated by three its 0 1 saidromponents,

" same color component." I

' the light from each of-parallellines and produce in color an image P r v and ob ect to appear in natural colors.-

' coming transmission channels are connecte through the repeating coils 290,

tures'in the scanningdisc and semi-transparentmirror system so as to cause of the three primary color light sources to be superimposed and the combined light projected at each instant for a given elemental area-into the eye of the ob-. server. In this arrangement the large ridlike receiving-lamps and their associatefdistributor commutator apparatus, one set for each primary color, are replaced by a corresponding number of scanning system for instantaneously directing the combined light of an elemental area into the eye of the observer. The three .in-

291, and 292 with the three amplifier and control networks 310, 320, and 330 whichinturn are connected with the "glow discharge lamps 350, 360, and 370 respectiv ly. Each one of these glow discharge lamps .emits light of one of the primary colors. I tion'ed with reference on asmall area 381 is combined and directed This scanning disc at the transmitting .station with which it is.

operated in synchronism and in phase by means of the synchronous driving "motor ele-- ment 185. The light from each of the three the three channels rapidlysweep over the. viewing field, formed by the opening in-the screen 382, in a seriesof the object-in the eye of the observer 390.

The invention has been described above as cases it may be desired to utilize only two colorsthe same principles,however,-applying generating and of light for successively and repeatedly;

a three dimensional. object, analyzing light reflected from the elemental areas of the said. object into primary color components, translating.

.the said components into ing. The invention therefore comprehends this modification.

What is claimed'is: t 1. The method of color television, conipris: directively moving a beam illuminating the elemental areas 0 electrical energy the light 'intensit and simultaneous y trans mitting the corresponding electrical energy correspondingto channel being continuously assigned to the components over. separate channels, --each' I 2 In. a system of electrical 's-cane tion "of movingobjects or pictures, a source lof light having'a continuous spectrum within the visible range, a plurality of stationary selective light sensitive-elements, eachresponmeans for synthesizing receiving lamps, each sources to produce an image of the sa1d obhave one light emltting area and a suitable These lamps are so ,posito the semi-transparentmirrors 362 and 37 2that-the light from each d successively and 'portional respectivel pr ma a scanning system elemental areas ofthe-said object and causlight from each elementallarea.

of the :fle'cted light from each illuminated to impinge siveto a diflere nt color of incident light meansfor successively directing a beam. 0

light from said sourceover the elemental areas of an object and causing reflected light from said object to simultaneously activate said light sensitive elements, transmission channels, sources of controlled tivation of said light sensitive elements, and light fromsaid currents, and producin simuling up said of images of ifierent taneouslyv a plurality primary colors respectively under control ofv said image currents, the corresponding'elemental :areas of said images being ]uxta-.-

posed.

' 4. In a system of electrical-image pfroducj dimensional objects, means for tion of three repeatedly illuminating the light of different colors in accordance with the light 210- ect.

3. The method of producing television.

d tion which comprises receiving a plurahty of utilized atthe transmitting station for setelemental areasof an object, stationary means I for simultaneously translating the light efiects of the said object into electrical currents proties of a plurality 0 595' to the mixing quanti 1 primary colors in said] object, means for producing light of each color, means for actuating said light producing means under the control of-said electric currents and means 'for o rality of stationary light receivlng means disposed around an object, each being tically- H synthesizing the light produced by sa d light I tioo its

light selectiveandhaving its maximum selectivity at a ditferent portion; of the visible spectrum, successively illuminating ing' reflected to 'impinge upon the said-light receiving 1 means, an amplifier andcontrol network connected'with each .lightsensitive cell and-a separate transmission channel leading-from f said networksto a receiving station. 1

each 7 v 6. A three color television systemcomprising a plurality of light sensitive cells dis- I -used-around an object, each being sensitive to adifierentband of wavelengths, a scanning' system successively illuminating 'elemental areas of ing from each ht sensitive 'annelleadthe. object and causingrev elemental area so and control of said networks to a receiving station, means at the said receivin station for converting the said amplified p otoelectric currents into light of the three pri mary colors, respectively, and means for causing the difl'erently colored light to simultaneously illuminate a group of elemental areas of the field of View correspondin to a single elemental area of the object eing scanned.

7. In a system of television for moving objects in natural colors, means for repeatedly illuminating a three dimensional object point by point and simultaneously activating at each instant primary color channels by reflected light from a given elemental area on an object thereby producing in each channel electric current corresponding in intensity to a primary color value of the said elemental area, each channel being continuously assigned tothe same color component.

8. Receiving apparatus for producing television images of objects or moving pictures in natural colors comprising means for re ceiving a plurality of currents representative respectively of primary color components of the light utilized at the transmitting station for setting up said currents, and electrooptical light generating means energized under control of said received currents for simultaneously producing a plurality of images of difierent primary colors respectively, the elemental areas of said images corresponding to a given elemental area of the object or picture being juxtaposed.

9. An electro-optical system for transmitting images of moving objects or pictures'in their natural colors comprising means for generating and directively moving a beam of light for repeatedly illuminatin an object point by point, simultaneously Emotioning separate color channels, each channel being continuousl assigned to the same color component, an means for transmitting all of the image currents necessary to the formation ofan image of the field scanned over said channels.

10. The'method of producing images of a field of view containing three dimensional objects which comprise generating and directively moving a beam of light for successively illuminating all of the elemental areas of said field with light of difi'erent colors, receiving the light difiusely reflected from each elemental area within a large solid angle upon color selective means, selecting light of different colors by said means and separately utilizing the selected light of different colors to set up electric currents, each current correspondingcontinuously to a given color component.

11. The method of producing images of a fieldof view containing three dimensional objects-which comprises generating and directively moving a beam of light'for succes-- sively illuminating all of the elemental areas of sai resale? of said field with light of different colors simultaneously, receivingthe light difiusely reflected from each elemental area within a large solid angle upo'n color selective means, selecting light of different colors by said means, and separately utilizing the selected light of difi'erent colors to set up electric currents, each current corresponding continuously to a given color component.

12. Means for generating and directively moving a beam of light for successively illuminating all of the elemental areas of a field of view containing three dimensional objects with light of difierent colors, and receiving means for receiving composite light containing all of said colors reflected from said areas over wide solid angles, said receiving means comprising stationary means for selecting color components of said composite light and separately utilizing said components to set up electric currents.

13. Means for generating, anddirectively moving a. beam of light for successively illuminating all of the elemental areas of a field of view containing three dimensional objects with light otdiflerent colors and receiving means for receiving light reflected from each of said areas over a Wide solid angle, said receiving means comprising stationary filters for selecting light of different colors and photoelectric means associated with said filters respectively for utilizing the selected light to set up electric currents.

14. Means for generating and directively moving a composite beam of light-for successively illuminatingall of the elemental areas of a field of view containing three dimensional objects and receiving means for receiving said composite light reflected from each of said areas over a wide solid angle, said receiving means comprising stationary means for selecting color components of said composite light and separately utilizing said components 'to set up electric currents,

15. Means for successively illuminating all of the elemental areas of afield of view containing three dimensional objects comprising a source of composite light, an apertured scannin disc and optical means for transmit ting light from said source to said elemental areas in the form ofa narrow beam, and receiving means for receiving light from each of said elemental areas over a wide solid angle, said receiving means comprising stationa means for selecting color components prising means for successively illuminating elemental areas of said field of view with composite light, and means for receiving light composite light and separately utilizreflected from each of saidelemental reas over a wide solid angle, said receiving eans comprising stationary color selective means of large area and disposed about said field of View, for selecting different color components of said reflected light, and means for utilizing said selected light to separately set up electric currents.

17. Means for producing an image in natural colors of a field of view containing three dimensional objects comprising means for generating and directively moving a composite beam of light for successively illuminating all of the elemental areas of the field of view, means for receiving light reflected from each of said elemental areas overa wide solid angle, said receiving means comprising moving a beam of electrically energizing said light producing I elements to cause them to pro uce light, the elements. of each group simultaneously producing light of difierent colors respectively.

In witness whereof, I hereunto subscribe my namethis Sth day of September, A. D.

HERBERT E. IVES.

the elemental areas of said field means for a receiving light reflected from each elemental area over a wide solid angle, said receiving means comprising a plurality of light sensit1ve means eachcontinuously selective of one I only of said colors. L

19. Means for producing a television image in color of a field of view containing three dimensional objects comprising means for generating and directively moving a beam of composite light for successively illuminating all of the elemental areas of the field and a plurality of stationary color selective light sensitive means of large effective area for.

receiving light reflected from each elemental area over a wide solid angle without the use of optical concentrating means and for. separately utilizing selected color components to set up electric currents. i

20. A television receiving system comprising a corresponding number. of grid glow discharge lamps, each emitting light of a difierentcolor and each responsive to an electric current for controlling t e intensity of the light from the said lamps. 3 e

21. Apparatus for producing television plurality of receiving channels, and a imagesm natural colors comprising groups i elements to cause them. to pro elements of each group producing light of a of light producing elements, and means for electrically energizing 'said. li

difierent color; and arranged in juxtaposed relation'to each other.

ima

ht producing uce light, the

A paratus for -producing television- .m natural colors comprising grou s of light producing elements, and means or I ioo 

